The present invention relates to a method for the determination of bilirubin and a composition suitable therefor. Bilirubin is present in serum and the determination of bilirubin in serum is useful for the diagnosis of liver function.
With regard to the determination of bilirubin, a method using diazonium salt of sulfanilic acid is widely used. In this method, bilirubin is determined by coupling the diazonium salt of sulfanilic acid with bilirubin and determining a formed pigment colorimetrically. However, the method has the following disadvantages.
(1) It is necessary to carry out the diazotization of sulfanilic acid using a strong acid each time just before use, because diazonium salt of sulfanilic acid is unstable. Therefore, it is somewhat troublesome to perform the determination.
(2) The reaction rate of bilirubin with diazonium salt of sulfanilic acid is slow and it takes about 15 to 30 minutes to complete the reaction.
(3) It is difficult to apply the method to the determination with an automatic analyzer because a strong acid must be utilized and metals are readily corroded in the presence of the strong acid.
Thus, development of a method for the determination of bilirubin which can easily be performed without utilization of strong acid in a short period of time has been desired.